What are the causes of difficult engine starting and how to deal with it?

[Gwen]

Reasons and solutions for difficult engine starting: 1. Overly rich air-fuel mixture: If the engine is difficult to start when hot, but can start normally when the accelerator pedal is fully depressed (no fuel injection when fully depressed), it indicates an overly rich mixture. In this case, remove the air filter element to release some of the accumulated rich mixture in the intake tract. 2. Excessive carbon deposits in the throttle system and bypass air passage: If the accelerator pedal feels much heavier than usual when first pressed each day, and the engine is difficult to start, but starts normally when the pedal is slightly depressed, it indicates excessive carbon deposits in the throttle. However, the engine may stall immediately when the accelerator pedal is released while driving. The throttle system and bypass air passage should be cleaned promptly, and recalibrated after cleaning to restore normal operation. 3. Excessive carbon deposits in the combustion chamber: During the first start each day, it may require 2-3 consecutive starts (as the initial fuel is absorbed by carbon deposits). In severe cases, sudden and intense shaking may occur, even causing the entire vehicle to shake. Clean the combustion chamber carbon deposits, and drive at high speed for 20 minutes after cleaning to resolve the issue.